Term Paper: Eating and Cholesterol

Coronary heart disease (CHD) remains the leading single cause of death in the United States today, and elevated serum cholesterol is widely recognized as being the risk factor responsible for myocardial infarction and CHD death; furthermore, a growing body of research supports the acceptance of hypercholesterolemia being as a causal and treatable agent in coronary artery arthersclerosis (Baum, Jennings, Manuck & Rabin, 2001).. According to statistics released by the National Institutes of Health (NIH), approximately half a million Americans die each year from coronary heart disease (Adams & Jennings, 1993). To date, researchers have determined that controllable risk factors such as the level of physical inactivity, smoking, overweight or obesity, high blood pressure, high blood cholesterol, and diabetes are all major influences on the development and severity of heart disease (Meadows, 2003). While coronary heart disease (CHD) is a complex, multifaceted health problem, there has been increased attention focused on dietary cholesterol and saturated fats as factors that also contribute to elevated blood cholesterol levels; in this regard, elevated blood cholesterol, specifically LDL (low density lipoprotein, the so-called "bad cholesterol") cholesterol, can lead to arteriosclerosis (a narrowing of the arteries that slows or blocks the flow of blood) and greatly increases the risk of heart attack (Adams & Jennings, 1993; Ulrich, 2002).

High blood pressure and elevated lipids represent a lethal combination; in fact, it has been estimated that fully 80% of those with hypertension also have high cholesterol levels (or hypercholesterolemia) and that 50% of these individuals will require some type of medication in order to lower their cholesterol to safe levels (Griffith & Wood, 1997). According to these authors, "For the most part, high blood pressure and high cholesterol are connected by a common denominator: poor lifestyle choices. Both diseases are more prevalent in sedentary and obese persons, and tobacco users" (Griffith & Wood, p. 240). High cholesterol levels are particularly dangerous for people with high blood pressure because excess cholesterol in the blood can become trapped in the crevices of arteries that have been damaged by chronic hypertension. As time passes, cholesterol accumulates along with other materials and constricts the opening of the affected arteries; if this blockage takes place in the coronary arteries that supply blood to the heart muscle, the result is a heart attack while blockages in the arteries that provide the brain with blood can result in a stroke (Griffith & Wood, 1997).

In a number of cases, blood cholesterol levels have been shown to be able to be lowered through diet and exercise, and the risk of CHD can thereby be reduced (Adams & Jennings, 1993). Cholesterol, though, represents just one causal factor that underlies CHD, and other risk factors for CHD include genetic predisposition, obesity, high blood pressure, diabetes, and smoking; however, just one factor, cholesterol, has been shown to be an important factor in this medley. In fact, an individual with a blood cholesterol level of 240 mg/dL (milligrams per deciliter) has a risk of CHD more than double that of an individual whose cholesterol is 200 mg/dL (NIH, 1990 cited in Adams & Jennings, p. 146).

The public awareness of the health risks typically associated with high cholesterol levels has also grown significantly; for example, a recent study found the percentage of Americans who were informed that their blood cholesterol level was too high increased from 11 to 20% between 1987 and 1990, and the number of people tested during the same period increased by 25% (Adams & Jennings, 1993). In this regard, there have been three dietary habits that have been commonly shown to contribute to elevated blood cholesterol levels:

1. Diets with high levels of saturated fatty acids which can elevate LDL cholesterol levels; these are found in both animal fats (e.g., butterfat) and plant oils; a number of tropical oils (e.g., palm, palm kernel, and coconut oils) contain particularly high concentrations of saturated fatty acids. "Fortunately, tropical oils are a minor component of the U.S. food supply" (Adams & Jennings, 1993, p. 146).

2. Diets with relatively high levels of cholesterol; dietary cholesterol is present only in foods and byproducts of animal origin (Adams & Jennings, 1993).

Although many Americans have responded to the threat represented by elevated blood cholesterol levels, significant problems continue to persist; for example, the average blood cholesterol level for adult Americans is approximately 210 mg/dL, and about 55% of the adult population have cholesterol levels of 255 mg/dL or higher (Adams & Jennings, 1993). In 1986, the National Center for Health Statistics estimated that 27.4 million adult Americans have cholesterol levels that placed them at high risk of CHD, and another 19.6 million adults could be placed in the "moderate risk" category; in addition, there has been an increasing amount of concern expressed over elevated cholesterol levels in children. According to Kagawa-Singer, Katz, Taylor, and Vanderryn (1996), Asian and Latino children have health problems comparable to those previously identified among white and African-American children. These authors report that, "Many were overweight and had low cardiovascular endurance and high cholesterol levels. In this Los Angeles sample, 38% of the Asian and Latino children had above-normal cholesterol levels for children, and 13% had cholesterol levels above normal for adults" (Kagawa-Singer et al., p. 149). By today's health standards, these rates would be even more alarming, with 40% of the boys and 45% of the girls being categorized as moderately to severely obese. Indeed, the authors predicted that these poor health trends would likely continue until better health education and physical education programs were provided for at-risk children and their parents (Kagawa-Singer et al., 1996). Likewise, a study conducted in New York found that approximately 80% of the 9-year-old children surveyed were consuming too much saturated fat and 60% were ingesting excessive amounts of dietary cholesterol (Adams & Jennings, 1993). Today, a number of researchers believe that high cholesterol levels in childhood can also contribute to an increased risk of heart disease and hypertension in adulthood (Adams & Jennings, 1993).

B. Rationale. Contemporary lifestyles frequently prevent consumers from enjoying balanced nutritional intake. Increasing pressures associated both with work and a decreasing amount of time being spent in the home has forced many Americans to "eat on the run"; further, despite increased public awareness, there is a clear trend today that Americans are becoming more obese; an article in American Demographics pointed out that "Americans claim to be concerned about nutrition, but demanding lifestyles and hunger pains are more likely to determine the foods they eat" (Are Americans Eating Better?, 1989, p. 30). Both high blood pressure and high lipids levels, though, are routinely treated with lifestyle modification regimens, including changes to diet and exercise. High blood pressure is a very common disease, but it is frequently symptomless; however, the condition can be successfully self-managed given the proper information, motivation, and medical guidance (Griffith & Wood, 1997). According to Griffith and Wood, if an individual has high cholesterol and high blood pressure that are related to obesity, a low-fat diet will simultaneously treat the hypertension and high cholesterol. Furthermore, a regular aerobic exercise program has been shown to lower blood pressure, reduce total cholesterol, and increase HDL (or so-called "good" cholesterol) levels (Griffith & Wood, 1997).

In their book, Behavior, Health and Aging, Baum et al. (2000) note that young and middle-aged men with relative hypercholesterolemia are known to have an increased risk of heart disease; in addition, the relationship between cholesterol and CHD risk is graded, and high cholesterol remains a risk factor in men with manifest CHD and in countries where the mean cholesterol concentration is relatively low. Furthermore, elevated serum cholesterol has been linked with preclinical atherosclerotic plaques in the carotid, femoral and coronary arteries (Baum et al., 2000).

Recent innovations have permitted the separation of total cholesterol into lipoprotein fractions; this has allowed researchers to better identify the relationship between serum lipids and atherosclerotic disease (Baum et al., 2000). In this regard, while it is closely correlated with total cholesterol, low density lipoprotein (LDL) cholesterol appears to represent a more accurate predictor of CHD; further, there is a growing body of evidence that points to an independent, inverse relationship between high density lipoprotein (HDL) cholesterol and CHD, whereas the role of elevated triglyceride levels in coronary atherosclerosis remains a point of debate (Baum et al., 2000). Recent studies have shown, though, that HDL and triglycerides are more important factors for women than men and, conversely, that elevated LDL cholesterol is an inconsistent predictor of heart disease in women (Baum et al., 2000).

C. Hypotheses and/or Objectives. The general hypothesis…
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